Calculator

How to use the calculator

1. Tap the keys or type on your keyboard. You don’t need to click into the display first: numbers and operators are picked up wherever you are on the page.
2. As soon as your calculation contains an operator, the answer appears underneath it. Press = or Enter to keep it.
3. After =, the result stays in the display with the calculation shown above it. Type an operator to carry on from the result, or a number to start a new calculation.
4. ⌫ (Backspace) deletes the last character and AC (Esc) clears the display. Copy copies what is in the display.

If you press two operators in a row, the second replaces the first, so 5 + × becomes 5 ×. The exception is a minus straight after × or ÷, which is read as a negative sign: 6 × −2 = −12.

Keyboard shortcuts

Order of operations

Many basic pocket calculators work out each step as you press the keys, so they give 20 for 2 + 3 × 4. This calculator reads the whole line and follows the standard order of operations: parentheses first, then powers, then multiplication and division, then addition and subtraction. That makes 2 + 3 × 4 = 14, and (2 + 3) × 4 = 20.

• A number directly in front of a parenthesis is multiplied: 2(3 + 4) = 14.
• A missing closing parenthesis at the end is added for you: 12 × (3.75 + 2.4 gives 73.8.
• Operations of the same rank are worked out from left to right: 100 ÷ 4 × 2 is 50, not 12.5.

How the % key works

Calculators don’t agree on what % should do, so here is exactly how this one handles it:

• After × or ÷, a percentage is simply divided by 100: 50 × 20% = 10, which is 20% of 50.
• After + or −, it is a percentage of the number in front of it: 80 + 15% = 92 (80 plus 15% of 80) and 200 − 25% = 150.
• Several in a row are applied one after the other: 1500 − 10% − 10% = 1,215, not 1,200, because the second 10% is taken from 1,350.
• Going backwards: to remove a 20% tax from a price of 144, divide by 120%: 144 ÷ 120% = 120.

Worked examples

• Tip and split: a restaurant bill of 64.50 with an 18% tip is 64.50 + 18% = 76.11. Then type ÷ 4 to continue from the result: 19.0275, or about 19.03 each.
• Weekly costs: a 3.75 coffee and a 2.40 bus ticket on five working days is 5 × (3.75 + 2.4) = 30.75.
• Price before tax: a receipt shows 144 including 20% VAT, so the price before tax is 144 ÷ 120% = 120 and the tax is 24.
• Discount: 20% off 1,250 is 1250 − 20% = 1,000.

For questions such as “what percent is 42 of 50?” or the percentage change between two numbers, the Percentage Calculator sets out the formula for you, and the Discount Calculator handles sale prices with tax.

Precision and large numbers

Like all software calculators, this one stores numbers in binary, where some decimals can’t be represented exactly – the raw result of 0.1 + 0.2 is 0.30000000000000004. Results are rounded to 12 significant digits, so you see 0.3. Very large or very small results are shown in scientific notation: 2^50 appears as 1.12589990684e15, meaning 1.12589990684 × 10¹⁵. Dividing by zero shows an error message instead of a result.

History

Each calculation you finish with = is added to History, newest first, up to the last 20. Click an entry to bring its result back into the display and keep calculating with it. The history only lasts while the page is open; Clear history empties it straight away.

FAQ

Why does my phone’s calculator give a different answer?

Usually because of the order of operations or the % key. A calculator that works step by step gives 20 for 2 + 3 × 4, while spreadsheets such as Excel read 80 + 15% as 80.15, because they treat 15% simply as 0.15. Check which rule your other calculator uses.

Can I type the whole calculation at once?

Yes. Type or paste it with * and / as the multiplication and division signs and press Enter.

Can I calculate powers, roots or sines?

Powers work here with ^. For square roots, trigonometry, logarithms and factorials, use the Scientific Calculator, which works the same way and adds those keys.